dmason said:
Thanks, I'll give them a call this week. I'd be most interested in high-Qts Alnico-magnet 12" and 15" drivers with decent Xmax and no huge guitar-speaker peak in the midrange - a 2X 12" + 2X 15" bass array would be just the ticket for the bass module.
As for the midrange, well maybe they have an ultra-performance studio-monitor grade midbass or midrange drivers, but frankly that's a lot more ambitious project that could take years. Then again, who knows, maybe they already make one. Time to call and find out.
I saw Jason Scheuner's name mentioned, and I'm presently working with him on a custom 12" woofer project. I have been extremely impressed with his thoroughness and attentiveness to detail. Hemptone is making two different prototypes for me, and I'll pick whichever one I like best. The idea of doing two different prototypes and me choosing was Jason's.
While Hemptone is capable of making custom drivers with either ceramic, neodymium, or alnico magnets, Jason's engineers recommended ceramic with shorting rings as offering the best performance for my particular application. They were perfectly willing to use neo or alnico if I wanted them to, but I figure it makes sense to listen to the engineers. I'm good friends with one of their long-term, very satisfied customers who manufacturers high-end loudspeakers, and he's the one who recommended A Brown Soun/Hemptone to me. The custom drivers they build for him use ceramic magnets and imho sound excellent. I don't think I'm at liberty to say who he is, as manufacturers often like to keep their suppliers confidential.
I doubt my woofers would be applicable to Lynn's project, as they are not designed with dipole operation in mind. But I did ask for an unusual custom feature, and Jason and his engineers were quick to jump on it and are excited to make it happen. Just mentioning that because imho that's the kind of engineering team that you'd want for an unorthodox custom project.
Duke
While Hemptone is capable of making custom drivers with either ceramic, neodymium, or alnico magnets, Jason's engineers recommended ceramic with shorting rings as offering the best performance for my particular application. They were perfectly willing to use neo or alnico if I wanted them to, but I figure it makes sense to listen to the engineers. I'm good friends with one of their long-term, very satisfied customers who manufacturers high-end loudspeakers, and he's the one who recommended A Brown Soun/Hemptone to me. The custom drivers they build for him use ceramic magnets and imho sound excellent. I don't think I'm at liberty to say who he is, as manufacturers often like to keep their suppliers confidential.
I doubt my woofers would be applicable to Lynn's project, as they are not designed with dipole operation in mind. But I did ask for an unusual custom feature, and Jason and his engineers were quick to jump on it and are excited to make it happen. Just mentioning that because imho that's the kind of engineering team that you'd want for an unorthodox custom project.
Duke
I finished testing a few drivers. Not all of them were mentioned in this thread, but I thought you guys might be interested anyway.
18 Sound 8NMB420
B&C 6NDL38
B&C 8NDL51
Beyma 6G40Nd
18 Sound 8NMB420
B&C 6NDL38
B&C 8NDL51
Beyma 6G40Nd
OB subs
http://www.audiocircle.com/circles/index.php?topic=47310.0
As Lynn had plans to use stereo Rhythmik Audio subs to supplement his gigantic OB, I thought I would mention a Servo controlled OB sub that will be released soon as a joint venture between GR Research and Rhymik Audio.
C
http://www.audiocircle.com/circles/index.php?topic=47310.0
As Lynn had plans to use stereo Rhythmik Audio subs to supplement his gigantic OB, I thought I would mention a Servo controlled OB sub that will be released soon as a joint venture between GR Research and Rhymik Audio.
C
Re: OB subs
Hi
Augerpro, thanks for all the effort you did. Very good to have some additional measurements of pro drivers.
What I found amazing is that the 8NMB420 shows strange harmonics. K2 is almost 20 dB below K3! I have a 6ND430 measurement from a magazine for comparison and this one doesn't show this effect, its almost vice versa with the 6ND430.
Did you measure harmonics at VERY low SPL levels?
Would be interesting to have CSD from that new drivers and looking forward to see TSP and FR as well. Wonder if these will become available in Europe as well.
Greetings
Michael
Hi
augerpro said:
Augerpro, thanks for all the effort you did. Very good to have some additional measurements of pro drivers.
What I found amazing is that the 8NMB420 shows strange harmonics. K2 is almost 20 dB below K3! I have a 6ND430 measurement from a magazine for comparison and this one doesn't show this effect, its almost vice versa with the 6ND430.
Did you measure harmonics at VERY low SPL levels?
chrismercurio said:
Would be interesting to have CSD from that new drivers and looking forward to see TSP and FR as well. Wonder if these will become available in Europe as well.
Greetings
Michael
I did not test HD at low levels, sorry.
You know I've always heard that paper cones have higher even order distortion that makes them sound warmer, and metal is higher in odd order which makes them sound more detailed. But that really isn't my experience when I've tested them. All the paper cones I've done have higher F3 than F2, while metal cones show know no real trend either way-except for the eventual peak in F3 due to cone breakup. Some like the TB W4-1337 actually have a much higher F2 than any other order, and it's titanium!
As far as higher orders it seems with paper the better ones keep F5 and up down in level, while the cheaper ones have very noisy spectrums.
But that's just what I've experienced, I'm a novice at speaker design, just trying to take as clean a measurement as I can.
You know I've always heard that paper cones have higher even order distortion that makes them sound warmer, and metal is higher in odd order which makes them sound more detailed. But that really isn't my experience when I've tested them. All the paper cones I've done have higher F3 than F2, while metal cones show know no real trend either way-except for the eventual peak in F3 due to cone breakup. Some like the TB W4-1337 actually have a much higher F2 than any other order, and it's titanium!
As far as higher orders it seems with paper the better ones keep F5 and up down in level, while the cheaper ones have very noisy spectrums.
But that's just what I've experienced, I'm a novice at speaker design, just trying to take as clean a measurement as I can.
Hi,
18'sound produces custom speaker for http://www.kv2audio.com/product.asp?ProdID=VHD2.0&ProdSeries=VHD , 8” speakersfeaturing AIC technology...
18'sound produces custom speaker for http://www.kv2audio.com/product.asp?ProdID=VHD2.0&ProdSeries=VHD , 8” speakersfeaturing AIC technology...
"Zaph measured some smaller drivers from A Brown Soun not too long ago. Perhaps someone can point Lynn to the link. If I remember right the curves looked okay, but the distortion did not."
http://www.zaphaudio.com/blog.html
Scroll down near the bottom for the hemptone speaker test. The 6.5" has a decent curve. Is the distortion that bad? I'm not real experienced with looking at CSD plots.
http://www.zaphaudio.com/blog.html
Scroll down near the bottom for the hemptone speaker test. The 6.5" has a decent curve. Is the distortion that bad? I'm not real experienced with looking at CSD plots.
Thanks Augerpro, the data you've measured is most informative. The most interesting driver of the group is the B&C 6NDL38, only one CSD peak to notch out instead of the multiple peaks and HF clutter we see with the others, there's also good HF rolloff and distortion characteristics too, the only downside of the B&C 6NDL38 being the 92 dB/efficiency.
Zaph's measurements of the 7" Hemptone have very nice CSD and FR curves, distortion above 1 kHz is pretty impressive as well, although distortion below 1 kHz is only average. The efficiency, though, is dismayingly low, even after compensating for the 3 dB difference between Zaph's full-space Theile/Small numbers and the half-space numbers used by most mfg's.
Zaph's measurements of the 7" Hemptone have very nice CSD and FR curves, distortion above 1 kHz is pretty impressive as well, although distortion below 1 kHz is only average. The efficiency, though, is dismayingly low, even after compensating for the 3 dB difference between Zaph's full-space Theile/Small numbers and the half-space numbers used by most mfg's.
Lynn,
I know you didn´t want to end up with "boutique" drivers, but this CSD is nicer:
http://www.supravox.fr/mesures/mes165GMF2.htm
The 8"ers are slower, but no irregularities as well.
I know you didn´t want to end up with "boutique" drivers, but this CSD is nicer:
http://www.supravox.fr/mesures/mes165GMF2.htm
The 8"ers are slower, but no irregularities as well.
Here's a CSD comparison between the factory measurement of the Supravox 165 GMF (at the top) and Augerpro's measurement of the B&C 6NDL38 (at the bottom). Speaking for myself, I'd take the 6NDL38 and apply a sharp notch filter at 4.1 kHz, fine-tuning the notch filter by ear and by using the CSD measurement, and using several drivers to confirm the repeatability of the tuning.
By contrast, the small ripples of the 165 GMF indicate a broad region of generalized breakup from 2~10 kHz. The breakup is well-controlled, but it is most certainly evident in the CSD and impulse response as a region of "clutter" lasting about 2 mSec. This cannot be filtered, by the way.
It is quite possible the ripples and overall clutter are artifacts of measurement - when I get a "cluttered" measurement like this, I look for reflections off (or inside) the test baffle, floor, microphone, or anything else. If measurement artifacts are ruled out, then I look for multiple emission surfaces on the diaphragm itself - you see this kind of clutter for electrostats and planar loudspeakers, for example.
With electrostats and planars, this kind of clutter isn't necessarily an indication of breakup per se; it's what non-uniform emission over a broad surface looks like in the time domain. With diaphragms driven from a small region, like direct-radiators, we call it "breakup", since the cone isn't accurately following the accelerations of the voice-coil assembly. But before making any judgements, the measurement system and test baffle must have very clean time responses - but that's true anyway for high-quality measurements in the time domain.
By contrast, the small ripples of the 165 GMF indicate a broad region of generalized breakup from 2~10 kHz. The breakup is well-controlled, but it is most certainly evident in the CSD and impulse response as a region of "clutter" lasting about 2 mSec. This cannot be filtered, by the way.
It is quite possible the ripples and overall clutter are artifacts of measurement - when I get a "cluttered" measurement like this, I look for reflections off (or inside) the test baffle, floor, microphone, or anything else. If measurement artifacts are ruled out, then I look for multiple emission surfaces on the diaphragm itself - you see this kind of clutter for electrostats and planar loudspeakers, for example.
With electrostats and planars, this kind of clutter isn't necessarily an indication of breakup per se; it's what non-uniform emission over a broad surface looks like in the time domain. With diaphragms driven from a small region, like direct-radiators, we call it "breakup", since the cone isn't accurately following the accelerations of the voice-coil assembly. But before making any judgements, the measurement system and test baffle must have very clean time responses - but that's true anyway for high-quality measurements in the time domain.
Attachments
Lynn I wonder if the B&C 6MDN44 would match the performance of the 6NDL38 while providing higher sensitivity? I may have test that one.
The 18sound 6NMB420 is also promising, although considering the better preformance of the B&C 8NDL51 over the 18Sound 8NMB420 I'm not expecting it to outperform the 6MDN44.
OTOH the 8NMB420 has real bass capability, and excellent distortion there too. I think the larger woofers in that family would be an excellent choice for bass/midbass duties. Better than anything I've seen in other PA woofers so far, from a distortion standpoint.
BTW I have the 8NMB420 and 6G40Nd on ebay if you or anyone else would like to try them for your own testing.
The 18sound 6NMB420 is also promising, although considering the better preformance of the B&C 8NDL51 over the 18Sound 8NMB420 I'm not expecting it to outperform the 6MDN44.
OTOH the 8NMB420 has real bass capability, and excellent distortion there too. I think the larger woofers in that family would be an excellent choice for bass/midbass duties. Better than anything I've seen in other PA woofers so far, from a distortion standpoint.
BTW I have the 8NMB420 and 6G40Nd on ebay if you or anyone else would like to try them for your own testing.
ttan98 said:
No no no. Just a monkey with a microphone, trying to make a valuable contribution to the diy community. If people really value my tests and would like to see this driver I *may* try to get one. Currently teh 6MDN44, 6NMB420, 6ND430and a Ciare driver are teh only ones I really want to test at the moment.